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New research sheds light on the surprising physical behaviour of exotic phases in liquid mixtures

In collaboration with Durham university, a scholar of theoretical physics from the University of Lincoln has published new findings about the surprising behaviour of exotic phases forming in liquids in Physical Review Letters – the world’s premier physics letter journal.

Dr Fabien Paillusson, Lecturer in the School of Mathematics & Physics, specialises in theoretical and computational modelling, the foundations of physics, machine learning and automated reasoning, logic and the philosophy of science.

His new paper, entitled Phase Separation on Bicontinuous Cubic Membranes: Symmetry Breaking, Re-entrance and Domain Facetting, is published in Physical Review Letters, a prestigious journal from the American Physical Society which publishes short, high-quality reports of significant and notable results in the full arc of fundamental and interdisciplinary physics research. Physical Review Letters provides readers with the most influential developments and transformative ideas in physics and is the most cited physics journal in the world.

Dr Paillusson’s new research discovered that surprisingly, a well-known lumping mechanism which occurs for instance when oil droplets merge together in water, does not occur on some exotic surfaces which appear naturally in detergent mixtures.

“If you pour olive oil in water, it will not mix but instead may form multiple small oil patches at the water surface which will eventually merge into a single circular large oil patch. This two dimensional lumping mechanism is in fact expected to occur for every mixture of different substances confined in a liquid film,” explained Dr Paillusson. “In the same way a 2D sheet of paper can be rolled into a 3D cylinder, liquid films can form spherical shapes (like soap bubbles do), but also so-called minimal shapes that are saddle-shaped at every point of the film. Our research has found that for some exotic minimal surfaces appearing naturally in detergent mixtures or in biology, this lumping mechanism does not necessarily happen.

“Using a similarity between this problem and an equivalent two dimensional magnetic system in a non-uniform magnetic field, we showed that small patches do indeed form but may remain trapped at specific locations on the film (corresponding to local “traps” of magnetic domains in the magnetic analogy). Depending on the substances’ properties and film composition, the number of trapped domains can be tuned at will and stable bridges can also form between them.”

The results of this research may further our understanding of pattern formation in biological systems, and could have important implications for spontaneous pattern forming in the design of smart materials.

Published by Fabien Paillusson

I am a theoretical and computational physicist. I am a senior lecturer in the School of Maths and Physics at the University of Lincoln. My interests lie in the modelling of complex matter, ranging from biological systems to powders, and in the foundations of physics.
View all posts by Fabien Paillusson